Two girls, ages 14 and 17, and a 17-year-old boy were at home in the 3400 block of Pacific Avenue near Laurel Street at about 9:35 p.m. Saturday when they heard a noise in an adjacent room, police Lt. Troy Dangerfield said.

The teens thought it was a ghost, but when they went to the bedroom on the third floor of the home, the boy noticed that the door to the room was closed, although he had remembered leaving it open, Dangerfield said.

The teens opened the door and found the man standing naked inside the room and masturbating. He looked at them and groaned, causing them to flee and call 911 from a neighbor's house, Dangerfield said.

Officers responded and found the man, identified as Tyrell Brown, 28, inside a closet. Brown was arrested on suspicion of lewd conduct, burglary, and possession of marijuana, according to Dangerfield.

Investigators found signs of forced entry into the home, which sits right outside the southern edge of the Presidio.